[phas-dept] Sep. 28 (Thursday) 4 PM - Physics and Astronomy Colloquium

[Heungman Park]

Fall 2017 Colloquium

Department of Physics & Astronomy

9/28, Thursday, 4-5 PM in Science Building 127

(coffee and cookies will be served at 3:50 PM)

Nuclear Engineering / Nuclear Physics

Applications of Ion Accelerators in Nuclear Materials Science
Dr. Lin Shao

Department of Nuclear Engineering - Texas A&M University - College Station

[https://urldefense.proofpoint.com/v2/url?u=https-3A__lh5.googleusercontent.com_vyCKlbjz3NXPRil0-2DkxeR3DHV70QJ1dcymZEFv-2Du5idqjztf5L3ej8HOF70QWfTexlA0m1goDEIxj9l0GTguNC1Cuj1JrN-5FpztiGbU-5Fa-5FEL5asO5glB-5FjBoaunbLyqH3uyCu7EXW&d=DwIF-g&c=oqyuZuih6ykib6aKiBq22_bich4AVfYGoLertJN0bEc&r=hjwEO_XYlnwAQWUGeaCrW47w4mK-Al28-BKyRvaivBs&m=tYAEptbJBKAquH0vOXoBa6FobDviDntE3A9xup9D79E&s=4YbWC-ibVgai9YN-hxSRsuCUQsEdTN80_xMO0foO8QM&e= ]

Dr. Lin Shao earned BS (1997) in Nuclear Physics at Peking University (China), and a Ph.D degree (2001) in Physics at the University of Houston. His Ph.D research topic was defect engineering in silicon. He worked as Director Postdoctoral Fellow at Los Alamos National Laboratory for studying hydrogen induced cracking in solids. In 2004, Dr. Shao joined Texas A&M University as Assistant Professor. He is now Professor and Director of Ion Beam Laboratory. Dr. Shao’s primary research interests are radiation materials science and the development of damage resistant materials. He has published over 200 journal papers, and holds 6 U.S. patents. More information about his research can be found at  https://urldefense.proofpoint.com/v2/url?u=http-3A__engineering.tamu.edu_nuclear_people_shao-2Dlin&d=DwIF-g&c=oqyuZuih6ykib6aKiBq22_bich4AVfYGoLertJN0bEc&r=hjwEO_XYlnwAQWUGeaCrW47w4mK-Al28-BKyRvaivBs&m=tYAEptbJBKAquH0vOXoBa6FobDviDntE3A9xup9D79E&s=g1i_GvnWaQQeHaX-jpgom4n-erBNlCZwJjVsWu1rR0A&e= 

Abstract

Neutron damage causes severe materials degradation, which limits safety and lifetimes of reactor components. Testing of various alloys in reactor environments, however, is unable to satisfy the needs from materials screening and materials developments. It is well known that currently fast reactors cannot accumulate more than 20 dpa (displacements per atom) per year in iron-base structural alloys. Currently available mixed-spectrum reactors (HFIR, ATR) in the USA cannot accumulate more than 10 dpa per year and usually less. On the other hand, next generation reactors require materials to survive at >400 dpa. The international radiation materials community has turned its attention to charged particle simulation techniques at vastly accelerated dpa rates as surrogates for evaluation of new alloy concepts and candidates, especially with respect to void swelling and irradiation creep. The various neutron-atypical artifacts preclude, however, an exact one-to-one ion-neutron comparison for confident near-exact prediction of swelling in a neutron environment. Claims were frequently made that predictive capability was possible, but such claims were never validated and should be taken with a grain of salt. In this talk, the most important "reactor-atypical" characteristics or "artifacts" of charged particle irradiation will be discussed. Such major artifacts include defect imbalance, flux effect and temperature shifting. After that, we will report our recent finding on nano-grained alloys, as examples of many on-going projects at Texas A&M University.

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